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Routines |
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Used by the routines at HandlerDoorClosed and HandlerTrapOpen.
Makes a burst of noise by sending the bits of the first 48 bytes of the ROM to the speaker. Bit 4 of the port is the speaker bit.
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| SoundsDoor | 42094 | LD BC,2096 | B=8 (the number of bits in a byte) and C=48 (the number of bytes). | |
| 42097 | LD HL,0 | HL=0 (the start of the ROM). | ||
| SoundsDoor_Byte | 42100 | LD E,(HL) | Fetch the next byte of the ROM. | |
| 42101 | INC HL | Move on to the next byte. | ||
| 42102 | PUSH BC | Stash the counters on the stack. | ||
| SoundsDoor_Bit | 42103 | RRC E | Rotate E right by one. | |
| 42105 | LD A,E | A=E. | ||
| 42106 | AND %00010000 | Keep only bit 4 (the speaker bit). | ||
| 42108 | OUT (254),A | Send it to the speaker. | ||
| 42110 | DJNZ SoundsDoor_Bit | Decrease the bit counter by one and loop back to SoundsDoor_Bit until it is zero. | ||
| 42112 | POP BC | Restore the counters from the stack. | ||
| 42113 | DEC C | Decrease the byte counter by one and loop back to SoundsDoor_Byte until all of the bytes have been sent. | ||
| 42114 | JR NZ,SoundsDoor_Byte | |||
| 42116 | RET | Return. | ||
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View the equivalent code in;
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